Awesome for spurring up this issue @timcliff! I see you have taken this from the MSP meeting. Two weeks ago I wrote a post about "What is value" (https://steemit.com/smt/@futurethinker/what-is-value). In here I give my take on it, if you have time left, I would really be interested what you think of my views on value.
I will think about writing another post about this!